1. Technical Field
Various embodiments of the present disclosure generally relate to resistance change memory devices.
2. Related Art
Generally, a resistive memory is a nonvolatile memory in which an internal resistance changes or varies according to an externally applied voltage or current. The changed resistance is written in the resistive memory in a nonvolatile manner. When the internal resistance changes between a plurality of levels, the resistive memory can store a plurality of pieces of logic information. The resistive memory can be classified into a resistance change random access memory (ReRAM) device, a phase change RAM device, a magnetic RAM device, and the like, according to how the internal resistance changes.
Meanwhile, in a resistance change memory device, when a voltage is applied to both ends of a variable resistance material layer, one or more conductive filaments in the variable resistance material layer are generated or dissolved, thereby forming or destroying a conductive bridge including the conductive filaments. Alternatively, an insulating interface layer can be generated or destroyed between the variable resistance material layer and an electrode layer by the applied voltage. The applied voltage thereby writes different resistance states in the resistance change memory device. Further, the converted states of the conductive bridge or the insulating interface layer are maintained in the variable resistance material layer even after the applied voltage is removed. Therefore, the written resistance states in the resistance change memory device can be stored in a nonvolatile manner.